Research On The Dissolution And Degradation Of Carbohydrates With Ionic Liquids

5-hydroxymethylfurfural(5-HMF)and levulinic acid(LA)can be prepared from biomass.Many useful organic compounds derive from 5-HMF and LA,which are expected to be new platform chemicals.In the traditional way,5-HMF and LA are prepared through hydrolyzation of biomass,using sulfuric acid and hydrochloric acid as catalysts.Because of the strong toxicity and corrosivity of inorganic acids,some severe problems occur,for example the production of acidic waste solid and liquid and corrosion of the equipments.So what we are trying to do is to dissolve and degrade carbohydrates like glucose,fructose,sucrose and cellulose with green solvent-ionic liquids,consequently obtain high yield of 5-HMF and LA.Several ionic liquids,[bmim]C1,[bmim]Br,[ibmim]Br,[(CH₂)₄SO₃Hmim] [HSO₄],[(Et)₃NH][HSO₄]and[bmim][CF₃SO₃]were synthesized,[bmim]C1, [bmim]Br,[ibmim]Br,[(CH₂)₄SO₃Hmim][HSO₄],[(Et)₃NH][HSO₄],[Hbim][BF₄] and[Hbim][CF₃SO₃]were characterized by IR,¹HNMR,¹³CNMR in this thesis.These ionic liquids were put into use of dissolution and degradation of carbohydrates. [bmim]C1 dissolved cellulose best with the highest solubility 12 wt%,followed by [bmim]Br and[ibmim]Br with the solubility 7 wt%,while[Hbim][BF₄], [Hbim][CF₃SO₃],[bmim][CF₃SO₃],[(Et)₃NH][HSO₄],[(CH₂)₄SO₃Hmim][HSO₄] were almost insoluble to cellulose.Microwave heating could significantly improve the dissolution rate of cellulose and slightly enhance the solubility.[bmim]C1 could be recycled.LA was not obtained with degradation of cellulose only with ionic liquids. 3.45%yield of LA was reached when the temperature was 112℃,the weight ratio of triethylammonium sulfate and water was 2,weight of cellulose accounted for 4%of all the system and the reaction time was 30 hr.We also got the yield of 5-HMF respectively 47.2%,29.2%,19.3%from the degradation of fructose,glucose and sucrose with ionic liquids.